Photographic elements



United States Patent Ofiice 3,370,046 Patented Feb. 20, 1968 1 Claim.(Cl. 260-78) This is a division of application Serial No. 318,515 filedOctober 24, 1963, US. Patent Number 3,312,554.

This invention relates to certain polymers which are useful additivesfor photographic gelatino silver halide emulsions, and to photographicsilver halide emulsions containing these polymers.

It is well known that certain gelatino silver halide emulsions losedensity as the wet-developed layer is dried. It is therefore desirableto provide photographic silver halide emulsions which have a reducedtendency to lose density upon drying.

One object of our invention is to provide certain polymers which areuseful additives for photographic gelatino silver halide emulsions.Another object of our invention is to provide photographic silver halideemulsions having a reduced tendency to lose density upon drying andafter development. A further object of our invention is to providephotographic emulsions which have increased maximum density. Otherobjects will appear herein.

These and other objects of our invention are accomplishedby providingpolymers which are the reaction product of an ester of an amino acidrepresented by the following structural formula:

R1- 3( ioR2 wherein R represents a substituent selected from the groupconsisting of H; CH -CH CH -OCH2OH3 and -CH CH S,CH and R represents asubstituent selected from the group consisting of CH 2 3;

H ll

with a polymer selected from the group consisting of polyacrylicanhydride, polymethacrylic anhydride, copolymers of alkyl vinyl other(the alkyl groups of which are from 2-4 carbon atoms) with maleicanhydride, or terpolymers of alkyl vinyl ether (the alkyl group being2-4 carbon atoms), ethyl acrylate and maleic anhydride.

In one embodiment of our invention we provide copolymers of acrylic acidor metha-crylic acid with N- acrylyl (or N-m'ethacrylyDamino acid ordipeptide esters, the amino acid and dipeptide esters being thosedescribed in the above structural formula.

polymers which are the reaction product of the amino acid and dipeptideesters described above with copolymers of alkyl vinyl ether with maleicanhydride, or terpolymers of alkyl vinyl ether, ethyl acrylate andmaleic anhydride.

We have found that when the polymers of our invention are incorporatedin gelatino silver halide emulsions, the maximum density of the drieddown layer is increased, and that there is a reduction in loss ofdensity on drying.

Our invention will be further illustrated by the following examples.

EXAMPLE 1 Reaction product of polywcrylic anhydride and N- acrylylethylalanz'ne Preparation of polyacrylic anhydride: Acrylic anl1ydride(20 g.) (prepared by the method of Brotherton, Smith and Lynn, J. Org.Chem., 1961, 21, 1283) was dissolved in dry dioxane (200 cc.) is a 250cc. round bottomed flask. Nitrogen was passed through the solution andazodiisobutyronitrile (0.4 g.) was added. The flask was sealed andplaced in a thermostated waterbath at 50 C. for 48 hours when thepolymer had completely precipitated. It was collected, washed thoroughlywith dry dioxane and dried under vacuum. The yield was 16 g. Reactionwith ethylalanine: A solution of polyacrylic anhydride (12.6 g.) in drydimethylformamide cc.) was added with stirring, while heating on asteambath, to a solution of ethylalanine (16 g.) in drydimethylformamide (50 cc.). The solution was stirred and heated on thesteambath for 18 hours. It was allowed to cool and the polymer wasprecipitated by pouring the solution into 3 liters anhydrous ether,washed with further portions of ether and dried under vacuum. The yieldwas 15 g.

The polymer was tested for its ability to reduce loss of density ofsilver halide emulsions by dissolving in water and adjusting the pH to6.5. The solution was then added at the rate of 30 grams polymer permole of silver to a coarse grain bromiodide emulsion which contained g.of gelatin per mole of silver halide. The mixture was then coated ontofilm support. Strips were cut and exposed for ,4 in an intensity scalesensitometer, developed for 3 minutes (at 20 C.) in the followingdeveloper:

Water to 1.0 liter.

fixed and washed in the usual manner. Densities were read while the filmwas wet and after the film has been dried in air at 120 F. and 20% RH.Characteristic curves were plotted for the wet and dry film' and thedensity differences on drying down were measured at specific densities.Speed was measured as the rel. log (IO/E) where E is the exposurerequired to produce a density of 0.85 above fog. In addition, two slopecriteria were calculated: (1) the toe slope-the slope of a line whichjoins two points on the curve which are at densities of 0.25 and 2.0above fog; and, (2) the shoulder slopea similar criteria where thepoints are at densities of 1.0 and 2.5 above fog. Speed, fog and maximumdensity (dry) were also measured. The results are shown in the following6 In another embodiment of our invention we provide 5 table:

Rel. Slope Du. Dens. loss at- Speed g y Toe Shoulder 1. 5 2. 5 3. 5

Control 286 2. 56 2. 94 10 3. 3 13 40 69 2 Parts Polymer Ex. 1 per 9parts gelatin"- 292 2. 82 3. 74 13 4. 3 02 06 20 3 EXAMPLE 2 Reactionproduct of polyacrylic anhydride and ethyl glycy'lglycine The copolyrnerwas prepared by the method described in Example. 1 fromethylglycylglycine (8 g.) and polyacrylic anhydride (6.3 g.). There wasobtained 8 g. of an almost colorless water soluble powder. The followingresults were obtained when tested as in Example 1:

in a pressure jar. Nitrogen was bubbled through the solution andazodiisobutyronitrile catalyst (0.8 g.) was added. The jar was closedwith a lid containing a rubber seal and placed in a thermostated waterbath at 50 C. for 7 days. The solution had become viscous and wasprecipitated in ether and Washed thoroughly in ether. Thispolymer (d g.)was then dissolved in dimethylformamide (150 ml.) and added withstirring to a solution of ethylalanine (18 g.) in dimethylformamide (50ml.). The solution .was

Rel. Slope Drnnx Deus. loss at Speed Fog Dry Toe Shoulder 1.5 2.5 3.5

Control 286 2. 74 3.5 .08 3.60 11 -.26 .46

2 Parts Polymer Ex. 2 per parts gelatin 290 2. 66 4.0 .09 4.0 06 18 24EXAMPLE 3 heated on the steambath for 2 /2 hours, stirring throughoutthis cried and the" ol mer was reci itated after Reaction product ofpolymethacrylzc anhydrzde and p p y p P ethylglycine Polymethaorylicanhydride was prepared from methacrylic anhydride by the methoddescribed in Example 1 for the preparation of polyacrylic anhydride.This polycooling, by pouring it into ether. It was washed with-3 furtherportions of ether and dried under vacuum. Yield The polymer was testedas described in Example .1. In

the following table are given the results whichwere obmer (15.4 g.) indimethylformamide (250 cc.) solution tained.

Slope Dmax Dens. loss at- Speed Fog Dry Toe Shoulder 1.5 2.5 3.5

Control 298 2.66 3.36 .09 3.65 --.14 .2G- -.6 2 2Parts PolymerEx.5per9parts gelatim.-- 293 2.70 3.58 .07 3.80 -.04 .18 .22

was reacted with freshly prepared ethylglycine (15 g.) EXAMPLE 6 indimethylformamide cc.) under the conditions of Example 1. A pale creampowder (18 g.) was obtained. On testing, as described in Example 1, thefollowing re sults were obtained:

Reaction product of copoly(ethyl vinyl ether, maleic anhydride) andethylglycine Ethyl vinyl ether, which had-been washed with water,

Bel. Slope mu! Dens. loss at Speed Fog Dry Toe Shoulder 1.5 2;5 3.5

Control 286 2. 74 3.5 .08 3.60 11 .26 .46 2.Parts Polymer Ex. 3 per 9parts gelatin. 291 2. 92 4. 3 11 4.0 O4 Nil 12 EXAMPLE 4 dried oversolid potassium hydroxide and distilled giving 50 a colorless liquidboiling at 36 C. (40 g.) maleic anhyl Cope ymer of g g gazgi andNmethaclylyl drlde (40 g.) and acetone (400 cc.), were placed m a Thecopolymer'was prepared by the method described in Example 1 frompolymethacrylic anhydride (15.4 g.)

glass pressure jar. Nitrogen was bubbled through the solution andazodiisobutyronitrile catalyst (0.8 g.) was added. The jar was closedwith a lid containing a rubber dissolved in dirnethylformamide (250 cc.)and ethylalaseal and was then placed in a thermostated water bath atnine (18 g.) dissolved in dimethylformamide (50 cc.). A hygroscopicpowder (16 g.) was obtained. The polymer was dissolved in water andaddedto a coarse grained emulsion as described in Example 1. Thefollowing results were obtained:

50 C. for five days. The solution had become viscous and wasprecipitated by pouring it, with rapid stirring, into industrialmethylated spirits. After stirring for 15 minutes, the polymer wasallowed to settle,-the'-s'upernatant liquor was decanted and replaced by'a fresh por- Slope Dmnx Dens. loss at p ed Fog Dry Toe Shoulder 1. 5 2.5 3. 5

Control 286 2. 74 3. 5 .08 3. 6 11 26 46 2 Parts Polymer Ex. 4 per 9parts gelatin... 285 2. 98 4. 3 07 4. 1 08 06 26 EXAMPLE 5 Reactionproduct of terp0ly(ethyl vinyl ether, ethyl acrylate, maleic anhydride)and ethylalanine A terpolymer was prepared by dissolving ethyl vinylether (12.5 g.), ethyl acrylate (12.5 g.), maleic anhydride (20 g.),acetone (200 cc.) and benzoyl peroxide (0.2 g.) 75

tion of methylated spirits (311.) and the mixture was 0 stirred forfifteen minutes. The washing process was then 6 to a solution ofethylglycine (9 g.) dissolved in dimethylstituted for ethylalanine. Thefollowing results were ob formamide (30 ml.). The solution was heated,while stirtained:

Rel. Slope Dmax Dens. loss at- Speed F g y Toe Shoulder 1.5 2.5 3.5

Control 284 2. 02 3.16 .07 3.35 .12 .25 .40 2 Parts Polymer Ex. 9 per 9parts gelatin 284 3.12 4. 60 16 3. 80 Nil 14 EXAMPLE 10 ring, on asteambath for 2 /2 hours and was then allowed to cool and precipitatedin ether as described in Example 10 Reaction product of c0poly(efhylvinyl ether-maleic 1. (Yield 14 g.). The polymer was tested as inExample 1. anhydride) and ethyl methionine The following results wereObtained The polymer was prepared and tested as described in Bel. SlopeDmnx Dons. loss at Speed Fog Dry Toe Shoulder 1.5 2.5 3.5

Control 298 i 2. 66 3.36 .09 3. 45 .14 .25 -.42 2 Parts Polymer Ex.6per9parts gelatin 296 2.80 3.94 .09 4.00 Nil .06 .(]4

EXAMPLE 7 Reactior, p' terpolflethyl vinyl ethyl Example 6 except thatethyl methionine (26.5 g.) was acry'ate malew anhydnde) and ethylglycmesubstituted for ethylglycine with the following results: A terpolymerwas prepared as described in Example 5,

Rel. Slope Du... Dens. loss at Speed o y W Toe Shoulder 1.5 2.5 3.5

Control 281 2. 54 2.90 .10 3. 13 .27 .47 2PartsPolymer Ex.10per9partsgelatin 283 2.80 3.60 .11 8.80 11 .18 18 and 15 g. was thenreacted with ethylglycine (14 g.) by EXAMPLE 11 the method described inExample 5. This yield of amino Reaction product of terpolyethyl vinylether ethyl acid derivative was 16.5 g. This polymer was tested asdescribed in Example 1. The following results were obamylmemaleicanhydride) and ethyl methionine tained. The polymers/5s prepared andtested as described in Slope a s- 2% 1 Speed Fog Dry Toe Shoulder 1.52.5 3.5

Control 298 2. 54 2.88' .07 3.2 20 .30 ".45 2 Parts Polymer Ex. 7 per 9parts gelatin- 295 2.88 4.10 07 3. 9 08 Nil Nil EXAMPLE 8 Example 5 excet that ethyl methionine 26 was sub- Reacnon product of polymethac'yhcanhydnde and ethyl stituted for ethy lalanine. The following resuitswere obmethio-nine' tamed: A copolymer was prepared as described inExample 4 Rel. Slope Dmax Dens. loss at Speed Fog V Toe Shoulder 1.5 2.53.5

Control 281 2.54 2.90 .10 3.25 13 -.27 -.4 2Parts Polymer Ex. 11per9parts gelatin 271 2.64 3.56 .10 3.85 16 23 .3

except that {ethyl methionine (26.5 was substituted for ethylalanine,and tested as described in Example 1. The following results wereobtained:

Rel. Slope Dmax Dens. loss at- Speed F g D y Toe Shoulder 1. 5 2. 5 3. 5

Control 284 2.62 3.10 .07 3.35 .12 .20 .46 2 Parts Polymer Ex. 8perQparts gelatin. 286 2.82 3.74 .10 4.10 .06 .06 16 y 7 I EXAMPLE 1').EXAMPLE 9 I Reaction product of polymethacrylic art-hydride and Reactionproduct 0 polyacrylic anhydride and ethyl ethylglutamate methlonme Thepolymer was prepared and tested as described in The polymer prepared andtested as described in Example 4 except that ethylglu-tamate (28 g.) wassub- Example 1 except that ethyl methionine (26.5 g.) was substitutedfor ethylalanine, with the following results.

Rel. Slope Dina! Dens. loss at- Speed Fog Dry Toe Shoulder 1.5 2.5 3.5

Control 281 2.6 3.56 09 3.56 .24 .40 .60

2 Parts Polymer Ex. 12 per 9 parts gelatin 290 2. 8 4.20 10 t 3. 12 2426 The foregoing examples demonstrate that the polymers The polymers ofour invention are highly useful, as in accordance with the inventioneffectively reduce loss shown in the foregoing examples, in gelatinsilver halide of density on drying, and also function to increase theemulsions. The ratio of the polymers of the invention to maximum densityof gelatino silver halide emulsions. Exthe gelatin of the emulsion isimportant, and may vary amples 13 and 14 below demonstrate theunexpected nafrom 1 to 4 parts by weight polymer to 9 parts by weightture of our invention in that certain polymers closely gelatin. Thepreferred ratio is 1 /3 to 2 /3 by weight related to those of theinvention fail to effectively reduce polymer to 9 parts by weightgelatin. loss of density upon drying of gelatino silver halide emul-Gelatin silver halide emulsions containing the polymer sions. of ourinvention may be sensitized with any of the well EXAMPLE 13 knowntechniques and additives in emulsion making. The

gelatin may contain a plasticizer, such as glycerine, and a gelatinhardener, such as formaldehyde. Other customary hotographic emulsionaddenda may be present in the The above copolymer, having specificviscosity of 0'.1- emulsion.

0.5 was treated with ethylglycine in a manner similar to 15 Thisinvention has been described in considerable dethat described in Example7 and tested photographically tail with particular reference topreferred embodiments Reaction product of c0p0ly(me-thyl vinylether-maleic anhydride) and ethylglycine as described in Example 1, withthe following results: thereof, but it will be understood thatvariations and modi- Rel. Slope Dma Dons. loss at Speed Fog Dry ToeShoulder 1. 5 2. 5 3. 5

Control 290 2. 80 3. 6 07 3. 58 34 60 2 Parts Polymer Ex. 13 per .9parts gelatin. 295 2. 76 4. 0 08 4. 0D 20 64 EXAMPLE 14 Reaction productof c0p0ly(ethylene-maleic anhydride) and ethylalanine fications can beeffected within the spirit and scope of 30 the invention as describedhereinabove and as defined in The above-identified copolymer was treatedwith ethylthe appended claims.

alanine and tested in the manner described in Example 1. We claim: Thefollowing results were obtained: 1. The reaction product of an aminoacid ester selected Rel. Slope Dmax Deus. loss at Speed Fog Dry ToeShoulder 1. 5 2. 5 3. 5

Control 287 3.16 3.78 .07 3. 76 26 .44 .E2 2 Parts Polymer Ex. 14 per 9parts gelatin. 286 2. 96 4.10 .07 3. 90 16 .36 48 from the groupconsisting of those represented by the fol- 1 The po ymers, copolymersand terpolymers which are lowing structural formula:

reacted with esters of amino acids and dipeptides include I polyacrylicanhydride and polymethacrylic anhydride, O

which are :homopolymers. The preferred copolymers of alkyl vinyl etherwith maleic anhydride are preferably of l the type wherein the twomonomeric components alternate 7 7 i in the polymer chain. The exactcomposition of the terwherein 1 represents a Substltuent Selected fromthe polymers of alkyl vinyl ether, ethyl acrylate and maleic groupconsisting of 3', z z anhydride is not known. The moles of the monomericsub 50 o stituent which are employed in polymerization of these gterpolymers ma be varied over a wide range, and preferably are about1.85, 0:625 and 1 mole, respectively, or, CHZCH2S CH3; and R2 l i aSubsmuent in parts by weight, 12.5, 12.5 and 20. The alkyl groupsSelected from the group conslstmg of OCH3; of the alkyl vinyl etherpreferably are 2 carbon atoms 50 but may be from 2-4 carbon atoms. H i 0The quantity of amino acid or dipeptide ester reacted l 1B' 6 with thepolymers employed in the invention may vary d over a wide range, andadvantageously is in excess of H one molar proportion of amino acid ordipeptide ester H for each anhydride group present, and preferably isfrom 7 9 1.5-2 molar proportions per each anhydride group of the with apolymer selected from the group consisting of polymer. polyacrylicanhydride, polymethacrylic anhydride, copoly- The exact chemical natureof the reaction product is mers of alkyl vinyl ether, the alkyl groupsof which connot known, but it is believed that under the conditions intain from 24 carbon atoms, with maleic anhydride and which the polymersare made, one of the carboxyl groups terpolymers of alkyl vinyl ether,the alkyl groups of liberated on opening the anhydride ring may form asalt. which contain 24 carbon atoms, ethyl acrylate, and maleic Whilepreliminary analysis points to the formation of a anhydride. partialamino acid salt, this has not yet been confirmed. The molecular weightof .the copolymers and terpoly- References cued mers which are reactedwith the amino acid and di- UNITED STATES PATENTS peptides esters mayvary over a considerable range, and 2,409,126 10/1946 Kenyon et al 260-4393 advantageously is such that a 5% solution of thepolymer I v inacetone at 25 C. has a'viscosity of 0.82.2 centistokes JOSEPH S R PnmaryEmmmer' and preferably is from 1.3 to 1.8 centistokes. I. KIGHT III,Assistant Examiner.

1. THE REACTION PRODUCT OF AN AMINO ACID ESTER SELECTED FROM THE GROUPCONSISTING OF THOSE REPRESENTED BY THE FOLLOWING STRUCTURAL FORMULA:R1-CH(-NH2)-CO-R2 WHEREIN R1 REPRESENTS A SUBSTITUENT SELECTED FROM THEGROUP CONSISTING OF H; -CH3; -CH2CH2 -COO-CH2-CH3 -CH2-CH2-S-CH3; AND R2REPRESENTS A SUBSTITUENT SELECTED FROM THE GROUP CONSISTING OF -OCH3;-OCH2CH3; -NH-CH2-COO-CH3 AND -NH-CH2-COO-CH2-CH3 WITH A POLYMERSELECTED FROM THE GROUP CONSISTING OF POLYACRYLIC ANHYDRIDE,POLYMETHACRYLIC ANHYDRIDE, COPOLYMERS OF ALKYL VINYL ETHER, THE ALKYLGROUPS OF WHICH CONTAIN FROM 2-4 CARBON ATOMS, WITH MALEIC ANHYDRIDE ANDTERPOLYMERS OF ALKYL VINYL ETHER, THE ALKYL GROUPS OF WHICH CONTAIN 2-4CARBON ATOMS, ETHYL ACRYLATE, AND MALEIC ANHYDRIDE.